Child proof closure assemblies are known in which entry to the closure assembly is brought about by rupturing a portion of the closure wall. However, in such child proof closure assemblies, the closure is child proof only for the initial opening. Once the closure wall is ruptured subsequent openings become easy and not child proof.
Child proof closure assemblies also are known in which an instrument is required in order to rotate the closure to open it, the closure being child proof in the sense that the closure cannot be opened without the instrument. However, with the rotation of the closure certain camming surfaces are additionally required thereby making the design of the closure assembly more intricate and more costly.
It is therefore an object of this invention to provide a closure assembly which is as child proof on its last opening as on its first opening.
A further object of this invention is to provide a closure assembly of simple construction which requires an instrument to open it but is free of camming surfaces.